The Thwaites glacier, a large glacier in Western Antarctica, is unstable and it may be impossible to stop it melting and flowing into the ocean, causing a 50cm rise in sea levels a new NASA funded study by US scientists shows.
The research published in the Proceedings of the National Academy of Sciences of the United States of America journal found that the giant glacier was likely to suffer instability linked the retreat of its grounding line on the seabed, which would lead to faster melting and shedding of its ice than previously thought.
If this happens then the whole of the Thwaites ice sheet could be lost in 150 years, even if global heating was reversed.
“It will keep going by itself and that’s the worry,” Alex Robel, an assistant professor at the US Georgia Institute of Technology and the leader of the study, told the Guardian.
Previous modelling simulations had suggested that serious ice loss in Antarctica wouldn’t start for another 600 years, but researches have now suggested it could happen sooner depending on the pace of global heating and the nature of the instability of each ice sheet.
“It could happen in the next 200-600 years. It depends on the bedrock topography under the ice, and we don’t know it in great detail yet,” Helene Seroussi, a jet propulsion laboratory scientist at NASA, told the Guardian.
Scientists were not able to give a more precise estimate of exactly how much ice the glacier would shed in the next 50-800 years because of data limitations and the fact that climate fluctuations are unpredictable. However, 500 simulations of different scenarios pointed to the glacier losing its stability and made the worst-case scenarios in sea level rises more not less likely.
Scientists Can’t Keep Up with the Pace of Climate Change
However, recent research suggests that scientists are having to revise their predictions as global heating increases faster than they initially anticipated. Ice loss from five Antarctic glaciers was five times faster than in the 1990s and had doubled in six years, according to recent research. Some sites have seen a reduction of more than 100 meters in their thickness in some places, as ice loss spreads deeper into the Antarctic interior.
The complete loss of the West Antarctic ice sheet would increase global sea levels by around 5 meters, enough for virtually all coastal cities in the world to become submerged.
A separate study published last week in the same US journal found that the amount of sea ice around Antarctica had seen a huge fall since just 2014.
Antarctic sea ice had been increasing for the last 40 years, before reaching a maximum in 2014 and then dropping off rapidly. The reason for this has still not been worked out by scientists but since 2014 Antarctica has lost the same amount of sea ice as the Arctic lost in 34 years.